<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title>getElementsByTagName获取checkbox进行全选</title>
		<style type="text/css">
			#myTable{ width: 900px; margin: 0px auto; background-color: #008000;}
			#myTable td,#myTable th{ background-color: white;}
			#myDiv{width: 900px; margin: 0px auto; height: 30px; line-height: 30px; 
			text-align: center;}
		</style>
		<!-- <script>======代码======</script> -->
	</head>
	<body>
		<table cellspacing="1" id="myTable">
			<tr>
				<th width="200">
                  <input type="checkbox" id="selAll" onchange="getStatus()" />全选
				<input type="checkbox" id="selAll" onchange="getInvert()" />反选
                        </th>
				<th width="200">姓名</th>
				<th width="200">性别</th>
				<th width="200">专业</th>
				<th width="200">爱好</th>
			</tr>
			<tr>
				<td><input type="checkbox"/></td>
				<td>刘备</td>
				<td>男</td>
				<td>软件开发</td>
				<td>抽烟</td>
			</tr>
			<tr>
				<td><input type="checkbox"/></td>
				<td>关羽</td>
				<td>男</td>
				<td>国际贸易</td>
				<td>喝酒</td>
			</tr>
			<tr>
				<td><input type="checkbox"/></td>
				<td>张飞</td>
				<td>男</td>
				<td>园林设计</td>
				<td>烫头发</td>
			</tr>
			<tr>
				<td><input type="checkbox"/></td>
				<td>赵云</td>
				<td>男</td>
				<td>平面设计</td>
				<td>抽烟</td>
			</tr>
			<tr>
				<td><input type="checkbox"/></td>
				<td>黄忠</td>
				<td>男</td>
				<td>影视制作</td>
				<td>玩游戏</td>
			</tr>
			<tr>
				<td><input type="checkbox"/></td>
				<td>小乔</td>
				<td>女</td>
				<td>高级护理</td>
				<td>唱歌</td>
			</tr>
		</table>
		<script>
			
			function getInvert() {
				var input = document.querySelectorAll('input');
				var num=0;
				for (let index = 2; index < input.length; index++) {
           			 if (input[index].checked) {
						input[index].checked=false;
						num++;
            } else {
                input[index].checked = true;
            }
			}
			if (num==input.length-2) {
				input[0].checked=false;
			}else{
				input[0].checked=true;

			}

		}
			
			 function getStatus() {
				var input = document.querySelectorAll('input');
				var num=0;
				for (let index = 2; index < input.length; index++) {
            if (input[index].checked) {
				num++;
            } else {
                input[index].checked = true;
            }
        }	
			if (num==input.length-2) {
			getInvert();
			
		}
				}
          
		</script>
	</body>
</html>